1. Field of the Invention
The invention relates in general to a balun device, and more particularly to a balun device with wave-filtering function.
2. Description of the Related Art
Along with the booming growth in the industry of wireless communication, more and more communication products are developed and provided, and how to improve the function of a communication product has become one of imminent goals to be achieved. In a communication product, the radio frequency module of a communication device includes an antenna, a low noise amplifier, a filter, a balun device, and so on.
After a wireless signal is received by the antenna of the communication device, a single port electrical signal outputted from the antenna will be outputted to the balun device. Then, the balun device converts the single port electrical signal into a dual port electrical signal, and further outputs the dual port electrical signal to a next-stage circuit for further processing. If the wave-filtering effect of the filter is not good enough, the balun device needs to be equipped with wave-filtering function. Thus, how to provide a balun device with wave-filtering function has become one of the imminent goals to the manufacturers.